KEF 104/2 tweeters


Good afternoon everyone. I just picked up a pair of KEF 104/2 speakers on CL. They are fully functional and I currently have them integrated in my system (Parasound Halo preamp and Nakamichi PA-5 amp).  I am concerned about the tweeters (one is slightly dented) and the ferrofluid. I've read some DIY fluid advice and am contemplating doing the work.  However, I've also heard that these tweeters are not top quality.  I've considered replacing them all together with Morel MTD 30s buy I can't seem to find any.  I would like to find a direct fit so I don't have to retro fit anything. Not sure about other available tweeters.... Also, do you believe it's worth while to do the surrounds while I have it pulled apart. Or any other suggestions for how to rehab them?? Thank you much! 

icarus12
Those tweeter sound good when overhauled.
Dismantle them gently kneed out the dent from behind, clean the magnet gap and voice coil of all old gunked up ferrofluid , and fill the gap with new ferrofluid (ebay), don’t over fill as the voice coil and former have to go in that gap too, I'd say half fill the gap.

It’s all on Google on what cleaner to use and how to do it.

Cheers George

I wouldn't de-value the 104/2,s with a different tweeter, the Kef T33 was a great tweeter when new they also used it in the 107/2,  just get some bad raps these days when old and crusty and half seized with dried up ferrofluid.

Also the T33 was designed to go lower than most tweeters, they cross it over at 3khz in these 104/2 so it's probably still doing audible work at 2khz.
Cheers George   
As georgehifi says the KEF T33 is a great tweeter. Once cleaned up and new ferrofluid applied it will be as good as new. It is a straightforward process. There are several online videos for the process and plenty of discussions on Audiokarma. The ferrofluid is readily available from Parts Express. 

As for the surrounds and donuts, it depends on which version 104/2 you have. The earlier version had rubber surrounds and foam donuts, so only the donuts may need replacing. The later version, which can be bi-amped, had foam surrounds and foam donuts, so both may have to be replaced. You can visually see the bottom woofer through the front port and check the condition of the donuts and surrounds.
If you have to take them apart, flip the bottom for the top woofer after the foam refit..., as this will give the natural over time sag of the drivers -- a chance to relax in the opposite position.

the in situ position of the woofers is bad for them (horizontal up and horizontal down), and.....over time, they tend to sag..so flipping them top for bottom when refoaming... is the remedy.

I don’t know if this can be done with the 104/2 woofers, but it should be done if at all possible.
Thank you all. I appreciate the feedback.  I did check out one video on changing out the ferrofluid but it didn't recommend what type of ferrofluid to use as replacement nor did it state how much to add??? Perhaps it's obvious when I get it apart. 
The ferrofluid is available from Parts Express. It doesn't take much. The ferrofluid comes in little tubes for different size tweeters. Each tube is enough for one tweeter. You need 2 tubes for 1 inch tweeters. They are about $6 each.
Terrific advice from everyone. I plan to change out the ferrofluid this weekend. Just inspected my surrounds and they are, in fact, the rubber type that must have come in the earlier non-biamped model.  The center donuts look decent as well. Thanks to all of you for helping 
Hi there.  I completed the ferrofluid replacement on both KEF 104/2 speakers based on your suggestions. Thank you.  Now... My right speaker is playing in a very muddy and muted way.  I thought I had noted it prior to the fluid change and had hoped that would remedy the issue but still there is a noticeable audible issue with vocals especially and overall output from the right speaker. All of the surrounds are intact (rubber) as are the donuts.  I swapped them temporarily to another set of speakers to make sure the issue wasn't elsewhere (amp, cables etc) but it's fine with other speakers. Could this be an issue with the caps?  I havent opened up the case around the mids to check them out.  Much obliged! 
I wouldn't get into the caps yet, there are a lot of them in the crossover. When you removed the front enclosure to access the tweeters, did you clean up the slip-on connecters and check if they have a good connection? If you didn't, I would check out those connectors first and make sure they aren't oxidized and they are all making a good connection. 

Also, visually are the midrange drivers all in good condition?
Thanks ljgerens. I will check the connections tomorrow (the connections for the tweeters looked very clean) and take a close look at the mids to see what kind of shape they're in. 
Pulled it apart again and all the connections look good, tight and clean.  I've read that you can't get into the mids because they aren't framed. Im not really sure how to access them. I've watched several videos of full 104/2 restorations but they don't do anything with the mids or even look at them in the videos. Am I missing something here?  Thank you again for your patience..
icarus12 OP
My right speaker is playing in a very muddy


One thing not mentioned (I assumed you did this, please say you did), are they making sounds when you put your ear to each and every driver, you could have a blown driver or xover if they aren’t making any sounds. Then no cleaning and changing of ferrofluid will help.

Cheers George
Hi George.  Thank you.  Yes, there is sound from the speaker in question, it's just muddled almost as if the speaker has a giant box over it when listening. 
The mid range drivers are an integral part of the enclosure and cannot be removed. You should be able to tell from looking at the front of them if there are any issues with them. 

Did the previous owner replace the foam donuts? Perhaps he connected up some wires incorrectly when putting everything back together.


I will check that tomorrow. Good idea!  I don't believe the donuts have been replaced but they appear in good shape. They arent crumbly or falling apart when I touch them. In my best estimation it doesn't seem they have been opened up at all. 
Yes, there is sound from the speaker in question,
What about from each individual driver, not just the speaker as a whole?
Put in a 3khz sine wave tone off the internet, not too loud to blow the tweeter, then put your ear to each of the 3 front drivers to hear if they are all emitting that tone.

Cheers George